Hypertension, a major risk factor for cardiovascular disease, is more prevalent and less controlled among ethnic minorities. African-Americans have almost twice the rates of hypertension in whites, and Mexican Americans with hypertension have about half the rates of control as whites. Despite the existence of therapies found to be efficacious in improving control and survival, hypertension control has made little or no progress in recent years. The literature has identified factors associated with underuse of efficacious therapies and poor blood pressure control, such as incomplete patient adherence to prescribed regimens, insufficient clinician follow-up to increase drug dosages or change medications, and long appointment waits. Efforts to improve control with the current armamentarium of proven therapies, however, have not matched strategies to underlying causes of underuse in specific local areas. The proposed hypertension project will tailor improvement strategies to the problems identified as underlying underuse among treated but uncontrolled hypertensive patients in East and Central Harlem, New York City. Along with the communities' 6 major health providers, we will first combine and qualitative and quantitative methods to identify specific patient, provider, and system problems, and customize interventions to address them. In a randomized controlled trial, we will then randomly assign 660 patients among 3 arms: nurse management, staff reminders, and usual care. During the 12-month trial, nurse managers will assess patients' needs, counsel them, address any access barriers, and follow-up with regular telephone contacts, convey information, including blood pressures from patients' self-monitoring, between patients and physicians to inform possible medication change; and ameliorate any systems problems. The staff reminder arm will test using less costly personnel to follow the same telephone schedule, but only remind patients to measure pressures and follow prescribed regimens. We will assess differences in blood reductions among the 3 arms as the primary outcome, and in quality of life, patient satisfaction, costs, and cost-effectiveness as secondary outcomes. The findings will provide new knowledge about the relationship between these changes and patient and clinician knowledge, attitudes, and behaviors. In partnership with community organizations and the policymakers, we will disseminate successful findings within these communities and throughout the state and the nation.